1. Field of the Invention
The present invention relates generally to ball joints and, more particularly, to a ball joint, which can prevent damage due to interference between contact parts even when the ball joint is tilted at a maximum angle, and can guarantee operational reliability.
2. Description of the Related Art
A ball joint has been widely used as connecting means with a spherical joint function.
The ball joint is mainly used to connect a steering shaft of a steering device or a headlamp leveling device installed in a luxury vehicle to adjust an irradiation angle of a headlamp depending on changed position of a vehicle body. In addition to the steering shaft or the headlamp leveling device, the ball joint is used as a means for connecting members of various devices.
FIG. 1 is a side sectional view illustrating a conventional ball joint.
The ball joint includes a ball stud 1 that approximately takes a shape of a sphere, and a holder 2 that seats the ball stud 1 therein to support rotation of the ball stud 1.
The ball stud 1 is generally coupled to a long bar-shaped shaft 3, and the holder 2 is coupled to an additional device or linkage, so that the device or linkage may be tilted at a desired angle with respect to a center of the ball stud 1.
Generally, an inclined surface is formed on an upper portion of the holder 2 to permit movement of the shaft 3, and a nut-shaped stopper 4 is provided on a portion of the shaft 3 adjacent to the ball stud 1.
The inclined surface and the stopper 4 function to limit a rotating angle of the shaft 3 relative to the holder 2.
However, when the shaft 3 of the ball joint rotates at a maximum angle, an outer surface of the shaft 3 receives load while being in contact with the inclined surface of the holder 2. In the case of having the stopper 4 as such, a portion of the stopper 4 maintains contact with an upper surface of the holder 2.
When the shaft 3 is subjected to a predetermined torque around a contact portion, the ball joint may be partially damaged. If the damage is serious, the ball stud 1 may be undesirably disjoined from the holder 2.
This becomes more serious when the shaft 3 is rotated in the state in which it is tilted at a maximum angle and is subjected to load.
In serious cases, the damage to the ball joint by the operation may lead to erroneous operation of the entire device or malfunction of the device.